1 files changed, 86 insertions, 0 deletions
diff --git a/vendor/futures-util/src/stream/try_stream/try_buffer_unordered.rs b/vendor/futures-util/src/stream/try_stream/try_buffer_unordered.rs
new file mode 100644
index 000000000..9a899d4ea
--- /dev/null
+++ b/vendor/futures-util/src/stream/try_stream/try_buffer_unordered.rs
@@ -0,0 +1,86 @@
+use crate::future::{IntoFuture, TryFutureExt};
+use crate::stream::{Fuse, FuturesUnordered, IntoStream, StreamExt};
+use core::pin::Pin;
+use futures_core::future::TryFuture;
+use futures_core::stream::{Stream, TryStream};
+use futures_core::task::{Context, Poll};
+#[cfg(feature = "sink")]
+use futures_sink::Sink;
+use pin_project_lite::pin_project;
+
+pin_project! {
+    /// Stream for the
+    /// [`try_buffer_unordered`](super::TryStreamExt::try_buffer_unordered) method.
+    #[derive(Debug)]
+    #[must_use = "streams do nothing unless polled"]
+    pub struct TryBufferUnordered<St>
+        where St: TryStream
+    {
+        #[pin]
+        stream: Fuse<IntoStream<St>>,
+        in_progress_queue: FuturesUnordered<IntoFuture<St::Ok>>,
+        max: usize,
+    }
+}
+
+impl<St> TryBufferUnordered<St>
+where
+    St: TryStream,
+    St::Ok: TryFuture,
+{
+    pub(super) fn new(stream: St, n: usize) -> Self {
+        Self {
+            stream: IntoStream::new(stream).fuse(),
+            in_progress_queue: FuturesUnordered::new(),
+            max: n,
+        }
+    }
+
+    delegate_access_inner!(stream, St, (. .));
+}
+
+impl<St> Stream for TryBufferUnordered<St>
+where
+    St: TryStream,
+    St::Ok: TryFuture<Error = St::Error>,
+{
+    type Item = Result<<St::Ok as TryFuture>::Ok, St::Error>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let mut this = self.project();
+
+        // First up, try to spawn off as many futures as possible by filling up
+        // our queue of futures. Propagate errors from the stream immediately.
+        while this.in_progress_queue.len() < *this.max {
+            match this.stream.as_mut().poll_next(cx)? {
+                Poll::Ready(Some(fut)) => this.in_progress_queue.push(fut.into_future()),
+                Poll::Ready(None) | Poll::Pending => break,
+            }
+        }
+
+        // Attempt to pull the next value from the in_progress_queue
+        match this.in_progress_queue.poll_next_unpin(cx) {
+            x @ Poll::Pending | x @ Poll::Ready(Some(_)) => return x,
+            Poll::Ready(None) => {}
+        }
+
+        // If more values are still coming from the stream, we're not done yet
+        if this.stream.is_done() {
+            Poll::Ready(None)
+        } else {
+            Poll::Pending
+        }
+    }
+}
+
+// Forwarding impl of Sink from the underlying stream
+#[cfg(feature = "sink")]
+impl<S, Item, E> Sink<Item> for TryBufferUnordered<S>
+where
+    S: TryStream + Sink<Item, Error = E>,
+    S::Ok: TryFuture<Error = E>,
+{
+    type Error = E;
+
+    delegate_sink!(stream, Item);
+}